Implemented a spike mixture prior for the local sigmas. Still undergoing
some testing.
Resolving conflicts.
Fixed bug that was seemingly not committed.
Resolving conflicts.
Merge branch 'structalign' of ssh://github.com/statalign/statalign into structalign_spike
Merged upstream changes from structalign.
Some bug fixes. Also, all branches are now fixed to global sigma for the
first half of the burnin, and then allowed to adopt local sigmas
thereafter, when spike prior is enabled. Still undergoing testing.
Abstracted the addition of weight increments after first half of burnin.
Merging structalign updates into structalign_spike.
Moved decision about incorporating ModelExtension into alignment
proposals into the ModelExtension itself, so that it also works with GUI
mode.
Merge branch 'structalign' into structalign_spike
Merge branch 'structalign' into structalign_spike

Conflicts:
	src/statalign/base/Mcmc.java
	src/statalign/mcmc/McmcModule.java
	src/statalign/model/ext/plugins/StructAlign.java
	src/statalign/model/ext/plugins/structalign/ContinuousPositiveStructAlignMove.java
	src/statalign/model/ext/plugins/structalign/HierarchicalContinuousPositiveStructAlignMove.java
Merge branch 'structalign_spike' of ssh://github.com/statalign/statalign
into structalign_spike

Conflicts:
	src/statalign/mcmc/McmcModule.java
	src/statalign/model/ext/plugins/StructAlign.java
Merged structalign_spike into main structalign branch.